There is a need in the field of cleaning agents and particularly in the field of cleaning agents for printing presses that will not degrade the rubber and that are safe to handle and environmentally friendly. As the preferred method of disposing of the removed ink and cleaning compositions is down the wastewater drain, without pretreatment, a safe, biodegradable cleaning composition is needed. There is also a need in this particular field for an environmentally friendly cleaning composition due to the high cost of disposing of cleaning cloths, used with non-environmentally friendly cleaning compositions, in an EPA approved manner. This practice requires printing businesses to hire outside cleaning companies with closed system washers to clean and dispose of the cloths used to wipe the presses. It is cheaper to buy new cleaning cloths, but disposing of the used cleaning cloths would violate EPA policy and result in a substantial fine if the cleaning procedure was not carried out.
By combining the composition disclosed in this patent with one of the readily available soy-based inks, already in use by most newspapers, the cost of cleaning the cloths will be avoided without violating the EPA policy at issue.
Presently, many cleaners being used are of high pH, contain ethylene glycol ethers, and/or are generally not stable emulsions. Some wastewater treatment plants do not want to accept
Lucas, U.S. Pat. No. 5,665,690:
The specification in U.S. Pat. No. 5,665,690 states that the composition be a “homogeneous, single phase solvent composition,” and therefore not an emulsion. Additionally, U.S. Pat. No. 5,665,690 proposes the use of a glycol ether as a secondary solvent alongside d-limonene. The present invention claims no co-solvent other than ethanol or water, and therefore falls outside the scope of U.S. Pat. No. 5,665,690.
Weltman, et al., U.S. Pat. No. 5,437,808:
Weltman teaches against the use of water in the composition proposed in U.S. Pat. No. 5,437,808. The composition claimed by U.S. Pat. No. 5,437,808 contains both esters and ethers. The proposed invention contains no esters and no ethers, and actually teaches against the use of esters because of their incompatibility with many of the elastomers used by the printing industry.
Swensen, U.S. Pat. No. 6,706,676
Swensen teaches the use of a standard anionic detergent emulsifier which is slow to biodegrade and is not environmentally friendly, whereas the current invention uses alkylated polyglucosides which are derived from sugars and plant oils and are quickly biodegradable and totally environmentally friendly. Prior art patent U.S. Pat. No. 6,707,676 contains monoethanolamine, a chemical that is toxic, corrosive, and flammable. Monoethanolamine is used to assist in ink dissolution and emulsion stability. The present invention uses ethanol or water to accomplish both of these goals with increased effectiveness and considerably improved safety. The current invention has superior material compatibility. Most organic solvents capable of removing ink from such rollers and sheets will swell or deteriorate the rubber of which they are composed. Some of the ingredients in the composition proposed by U.S. Pat. No. 6,706,676 are dibasic esters. Esters are highly incompatible with most natural and synthetic rubbers, including the type of rubber comprising most print rollers and sheets: NBR or nitrile butadiene rubber.
An ingredient in U.S. Pat. No. 6,706,676 used as an emulsifier is dodecylbenzene sulfonate. Though compatibility tests for elastomers with dodecylbenzene sulfonate have not been published, the very closely related chemical dodecylbenzene has been found to be highly incompatible with most types of rubber, including NBR. Our cleaning composition lacks any such ingredient, and instead uses mild, but effective surfactants to accomplish the same task.
One of the most common complaints made by pressmen about environmentally responsible cleaning systems is that they are too slow to evaporate. Slow evaporation means more time spent cleaning the press, and therefore less efficient pressroom operation. Our cleaning composition is designed to evaporate quickly without reducing effectiveness and safety. One of the stated goals of prior art patent U.S. Pat. No. 6,706,676 is to produce a composition “mainly of low volatility components”. Low volatility equals slow evaporation which equals less efficient pressroom operation.